Field
Apparatuses and methods consistent with the exemplary embodiments relate to a system and method for non-invasive registration between a patient and a patient's three-dimensional (3D) image for registration of a position and a pose between a patient and a patient's 3D medical image, and more particularly to a system and method for non-invasive registration between a patient and a patient's three-dimensional (3D) image, which can align a patient's 3D medical image with a patient by a non-invasive method using a feature point based on a blood vessel pattern, where a patient's blood vessel is extended, without using an artificial fiducial marker.
Description of the Related Art
In general, a minimally invasive surgery is a surgery method that 3˜4 small holes are pierced through a skin and an endoscope and a narrow and long surgical instrument are put into the holes so as to minimize skin incision. Such a minimally invasive surgery has been annually increased due to less pain and short recovery time along with minimal scar left when compared to general surgery.
However, in the minimally invasive surgery, an operating surgeon cannot directly see an affected area and therefore indirectly checks an image gained from the endoscope through a monitor. At this time, it is not easy to observe a targeted affected area because a view direction of the surgeon is different from a direction of the endoscope and the endoscope is short-sighted. Further, it is unintuitive and thus difficult to treat the affected area by controlling a surgical instrument while watching an image from the endoscope.
Meanwhile, a non-invasive surgery is a surgery method that ultrasonic waves, radiation, magnetic field, etc. are used for treatment without skin incision. In this surgery method, an operating surgeon cannot directly see an affected area and also cannot use the image from the endoscope in real time. Therefore, surgery navigation has been required to guide the surgical operation of the operating surgeon during an operation through a three-dimensional (3D) medical image (computer tomography (CT), a magnetic resonance imaging (MRI), etc.) of a patient taken for a diagnosis and a surgical plan before the operation.
For the surgery navigation, a patient's 3D medical image has to be first aligned with an intraoperative patient with respect to coordinates. That is, if coordinate transformation between a medical image coordinate system of the 3D medical image and a patient coordinate system (i.e., a coordinate system arbitrarily set up in the real world) is known, it is possible to determine what position of a patient a certain position on the medical image corresponds to. This is called patient-image registration.
As a method generally used for the patient-image registration, there is a method of performing the patient-image registration by taking a medical image in the state that fiducial markers are attached to a patient, and aligning the fiducial markers from previously taken medical image with the fiducial markers that is attached to the patient.
In the case of using the fiducial marker, there are an invasive method of fixing the fiducial markers to a patient's bone, and a non-invasive method of attaching the fiducial marker on a patient's skin. The invasive method burdens a patient due to scar on bone even though registration is relatively precise. On the other hand, the non-invasive method is not applicable to microsurgical operation due to low precision.
Accordingly, a markerless patient-image registration method without using the fiducial markers has recently been researched, in which 3D medical image registration is performed using a patient's two dimensional (2D) sectional image based on ultrasonic waves or X-rays, or using a 3D scan model of a patient's skin surface.
However, the registration between the 2D sectional image and the 3D medical image needs long calculation time and is vulnerable to soft tissue transformation of a human body. Also, the registration between the 3D scan model of a patient's skin surface and a skin surface model extracted from the 3D medical image may have a large error due to change in shape of the skin surface.
Consequently, patient-image registration method which does not use the fiducial markers and is minimally affected by change in a patient's soft tissue and a skin surface are required.